.

qwen/nodejs/node_modules/eslint/lib/shared/deprecation-warnings.js

@@ -0,0 +1,58 @@
+/**
+ * @fileoverview Provide the function that emits deprecation warnings.
+ * @author Toru Nagashima <http://github.com/mysticatea>
+ */
+"use strict";
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const path = require("path");
+
+//------------------------------------------------------------------------------
+// Private
+//------------------------------------------------------------------------------
+
+// Definitions for deprecation warnings.
+const deprecationWarningMessages = {
+    ESLINT_LEGACY_ECMAFEATURES:
+        "The 'ecmaFeatures' config file property is deprecated and has no effect."
+};
+
+const sourceFileErrorCache = new Set();
+
+/**
+ * Emits a deprecation warning containing a given filepath. A new deprecation warning is emitted
+ * for each unique file path, but repeated invocations with the same file path have no effect.
+ * No warnings are emitted if the `--no-deprecation` or `--no-warnings` Node runtime flags are active.
+ * @param {string} source The name of the configuration source to report the warning for.
+ * @param {string} errorCode The warning message to show.
+ * @returns {void}
+ */
+function emitDeprecationWarning(source, errorCode) {
+    const cacheKey = JSON.stringify({ source, errorCode });
+
+    if (sourceFileErrorCache.has(cacheKey)) {
+        return;
+    }
+
+    sourceFileErrorCache.add(cacheKey);
+
+    const rel = path.relative(process.cwd(), source);
+    const message = deprecationWarningMessages[errorCode];
+
+    process.emitWarning(
+        `${message} (found in "${rel}")`,
+        "DeprecationWarning",
+        errorCode
+    );
+}
+
+//------------------------------------------------------------------------------
+// Public Interface
+//------------------------------------------------------------------------------
+
+module.exports = {
+    emitDeprecationWarning
+};